The Geologic Time Scale

Question 1

Refers to the divisions of earth’s history based on life forms

Answer 1

Geologic Time Scale

Question 2

are the largest intervals of geologic time with duration of hundreds of millions of years. The geologic time scale is divided into 4 major units

Answer 2

Eon

Question 3

The geologic time scale is divided into 4 major units

Answer 3

Hadean Eon
Archean Eon
Proterozoic Eon
Phanerozoic Eon

Question 4

there were fewer life forms. These life forms are more difficult to identify and the rocks have been disturbed often. An informal name given to the first three eons of the geologic time scale

Answer 4

precambrian

Question 5

began 4.5 to 4 billion years ago. Known as the rock less eon. Except for the meteorites, no existing rocks on Earth today are from the Hadean eon. During this time, Earth was molten, and it would only solidify as it cooled.

Answer 5

hadean eon

Question 6

began 1.5 billion years ago. during the Archean eon that single-celled organisms, such as blue-green algae, archeans, and bacteria, first appeared. It is the beginning of free oxygen in the atmosphere.

Answer 6

archean eon

Question 7

the first era of the Archean Eon of the geologic record. Earth’s surface was dominated by volcanic activity during this era. The atmosphere consisted mainly of carbon dioxide and water vapor.

Answer 7

eroarchean era

Question 8

The earliest confirmed evidence of life comes from this era, and Vaalbara, one of Earth’s earliest supercontinents, may have formed during this era.

Answer 8

paleoarchean era

Question 9

the beginning of the Pongola glaciation on earth, which occurred in what is now South Africa. This was the first climate disaster on earth, as ice sheets covered areas of Swaziland and South Africa.

Answer 9

mesoarchean era

Question 10

represents a key period in Earth’s evolution, as it recorded a transition in tectonic style, from an Early-Archean Earth dominated by episodic-overturn/stagnant-lid regime to a Proterozoic Earth in which modern- style Plate Tectonics became progressively established.

Answer 10

neoarchean era

Question 11

began 2.5 billion years ago and ended 542 million years ago. the first continents appeared. This was also the time when continents merged into a single landmass called Rodinia. The Proterozoic eon is marked by the appearance of multicellular animals like sponges and the mass extinction of these organisms.

Answer 11

proterozoic eon

Question 12

had given rise to crown eukaryotes, which are the ancestral organisms from which all modern eukaryotic lineages have evolved. This era is also marked by the earliest global-scale continent-continent belt collisions known.

Answer 12

paleoproterozoic era

Question 13

are the breakup of the Columbia supercontinent, the formation of the Rodinia supercontinent, and the evolution of sexual reproduction. This era is marked by the further development of continental plates and plate tectonics.

Answer 13

mesoproterozoic era

Question 14

is characterized by the most important climatic, tectonic and paleo - evolutionary changes in the Earth’s geological record

Answer 14

neoproterozoic era

Question 15

The first life forms with parts, such as shells, scales, and bones and teeth, appeared during the Phanerozoic eon. The fossils of these life forms are great tools in the study of the history of the Phanerozoic eon.

Answer 15

phanerozoic eon

Question 16

means “ancient life”. The supercontinent Pangaea was formed during the this era.

Answer 16

paleozoic era

Question 17

represents the major increase in number of invertebrates.

Answer 17

cambrian to ordovician period

Question 18

represents the evolution of fishes.

Answer 18

silurian to devonian period

Question 19

represents the evolution of amphibians.

Answer 19

carboniferous to permian

Question 20

means “middle life”. It’s a popular time division because it was when dinosaurs dominated and lived on dry land.

Answer 20

mesozoic era

Question 21

came after a recent extinction that left only a few animals. One of these animals, the Archosaur, became the prototype for the dinosaurs in the Jurassic and Cretaceous period. Today, the only known descendants of Archosaurs are birds and crocodile-like animals.

Answer 21

triassic period

Question 22

was the Golden Age of dinosaurs. Animals from the Triassic grew, spread and diversified in the Jurassic Period, making some of the most famous dinosaurs we know now today, like the T-rex. Some dinosaurs began to develop feathers, bone structures that resembled modern-day birds. This was a period when reptiles ruled all areas: land, water and air.

Answer 22

jurassic period

Question 23

marks the final period of the Mesozoic era, when all living beings reached big and great sizes, but also faced harsh competition.

Answer 23

cretaceous period

Question 24

recent life’. this era comes directly after the Mesozoic era. This era is well-known for introducing flowering plants, birds, insects and mammals, including humans.

Answer 24

Cenozoic era

Question 25

abruptly when a meteorite slammed into the earth, leading to a mass extinction that wiped out about 75% of all species on Earth. This left only a few surviving mammals and reptiles that grew to be the animals we know now in modern day.

Answer 25

tertiary period

Question 26

 “old recent”
 was the complete absence of dinosaurs and other reptilian groups
 rapid proliferation and evolution of mammals
 warm and humid climate
 continents moved closer to their current positions

Answer 26

paleocene epoch

Question 27

 ”dawn of the recent”
 marks the first appearance of fossil
 global climate is warm and rainy
 noted for the expansion of mammalian stocks

Answer 27

eocene epoch

Question 28

 ”few recent forms”
 a global expansion of grassland and forest region
 sudden decrease in earth’s temperature
 noted for the expansion of mammalian stocks

Answer 28

oligeocene epoch

Question 29

 ”less recent”
 warmer global climate than the previous epochs
 many fauna and flora died and others adapted to the drying world

Answer 29

miocene epoch

Question 30

 ”continuation of the recent”
 global climatic cooling
 growth of mountains
 animals flourished, other species died out

Answer 30

pliocene epoch

Question 31

marks the time when humans started growing and thriving until present.

Answer 31

quaternary period

Question 32

 the “Great Ice Age”
 the last time great diversity mammals lived like the mammoth

Answer 32

pleistocene epoch

Question 33

 the ”Age of Man”
 All recorded human history occurred in this epoch

Answer 33

halocene epoch